<template>
	<div>
		<router-link
			 tag="div"
			 to="/" 
			 class="header-abs"
			 v-show="showAbs"	
		 >
			<div class="iconfont header-abs-back">&#xe65b;</div>
		</router-link>
		<div 
			class="header-fixed" 
			v-show="!showAbs"
			:style="opacityStyle"
		>
			<router-link to="/">
				<div class="iconfont header-fixd-back">&#xe65b;</div>
			</router-link>
			景点详情
		</div>
	</div>
</template>

<script>
	export default {
		name: 'DetailHeader',
		data () {
			return {
				showAbs: true,
				opacityStyle: {
					opacity: 0
				}
			}
		},
		methods: { 
			handleScroll () {
				const top = document.documentElement.scrollTop
				if (top > 60){
					let opacity = top/140
					opacity = opacity > 1 ? 1 : opacity
					this.opacityStyle = { opacity }
					this.showAbs = false
				}else{
					this.showAbs = true
				}
			}
		},
		activated () {
			window.addEventListener('scroll', this.handleScroll)
		},
		deactivated () {
			window.removeEventListener('scroll', this.handleScroll)
		}
	}
</script>
 
<style lang="stylus" scoped> 
	@import '~styles/varibles.styl'
	.header-abs	
		position: absolute
		left: .2rem
		top: .2rem
		width: .8rem
		height: .8rem
		line-height: .8rem
		border-radius: .4rem
		background: rgba(0, 0, 0, .8)
		text-align: center
		.header-abs-back 
			color: #fff
			font-size: .4rem
	.header-fixed
		z-index: 2
		position: fixed
		top: 0
		left: 0
		right: 0
		height: $headerHeight
		line-height: $headerHeight
		text-align: center
		color: #fff
		background: $bgColor
		font-size: .32 rem
		.header-fixd-back
			position: absolute
			top: 0
			left: 0
			width: .64rem
			text-align: center
			font-size: .4rem
			color: #fff		
</style>